Processes of laminating polymer films over spaced narrow webs are known. Relevant patents regarding lamination of narrow spaced webs include U.S. Pat. Nos. 3,477,126, 3,656,513 and 4,859,259. The ""126 patent discloses a method of making a strip conductor material where webs of aluminum, which are spaced apart on a roll, are unrolled and an extruder applies a layer of plastic material to one side of the webs. The wide extruded layer is later slit to form individual aluminum webs with the plastic material covering one surface of the individual webs and overhanging both sides. The ""513 patent discloses a method of manufacturing strip material for fabricating container bodies wherein a single wide roll of cardboard is slit, skived and extrusion coated with plastic on both sides. The ""513 patent shows turning bars for steering the individual cardboard strips into subsequent manufacturing processes after the webs have been slit and laminated. The ""259 patent discloses a process and apparatus for fabricating re-closable plastic bags wherein a double set of interlocking closure strips are unrolled from a reel, the strips are separated and a polymer film is extruded onto the strips. The polymer film is then slit, folded around a folding apparatus and wound upon reels.
Processes of dynamically bonding thermoplastic films are also known. U.S. Pat. No. 4,919,738 herein incorporated by reference teaches a method and apparatus for dynamically mechanically bonding laminate layers, including at least one thermoplastic layer, by a pressure biased nip and an opposed roller.
The present invention is directed to a method and apparatus for laminating polymer to another material where the polymer has a different width than the material to which it is laminated.
One aspect of the present invention is directed to process and apparatus for laminating a wide web of nonwoven with narrow strips of polymer.
Another aspect of the invention is directed to a process and apparatus to continuously perform web splitting, folding, guiding and laminating steps in a single unit. A single wide web of nonwoven is slit, folded, spaced apart by a predetermined distance by the use of turning bars and steered into a subsequent lamination process. Depending on the spacing between folded webs, each strip of polymer may include a loose flap on either side which may be suitable for forming a barrier cuff in a diaper or other hygiene product. The spacing between folded webs determines the width of a loose polymer flap which is formed.
Yet another aspect of the invention is directed to a process and apparatus to continuously perform web splitting, separating, guiding and laminating steps in a single unit. A single wide web is slit, separated by the use of turning bars and steered into a subsequent lamination process.
This invention provides an apparatus and method of producing the laminate on high speed production machines at line speeds of about 300-1,200 feet per minute (fpm). It involves in-line slitting of a single wide web of material, turning, separating, and subsequently laminating the webs. More specifically, a web is unrolled from a wide roll of nonwoven material. The incoming web is slit into narrow webs by score slitting, shear slitting, razor slitting, laser, water jet slitting or ultrasonic slitting, the narrow webs, which may be folded at a folding plate, then move down the line to turning bars which are displaced one from the other by a desired web separation distance. The spaced webs are then guided to an embossing or laminating station where the spaced webs are fed through nip rollers to adhere molten or solid polymer to the webs. More specifically, the webs may be introduced into a nip of rollers for extrusion lamination with a polymer film or may be dynamically mechanically bonded to a solid polymer film. When laminating the nonwoven to a polymer extrudate, the extrudate is extruded into the nip at a temperature above its softening point to form a film. The compressive force between the webs and the extrudate at the nip is controlled to bond one surface of the web to the film to form the laminate. The wide laminate layer is then slit and may be unfolded prior to winding on a take-up reel. When Laminating to a solid film of polymer the film may be slit and separated, as described above, and then dymanically bonded to a wide nonwoven web.
Other benefits, advantages and objectives of this invention will be further understood with reference to the following detailed description.